Suction box covers



June 27, 1961 R. E. cARREl.

sUcTIoN Box covERs 4 Sheets-Sheet 1 Filed March 19, 1957 oo o ocio@ U o o o TPLQ o ATTORNEY R. E. cARREL 2,990,015

sUcTIoN Box covERs 4 Sheets-Sheet 2 June 27, 1961 Filed March 19, 1957 June 27, 1961 R. E. cARREL sucTIoN Box coms 4 Sheets-Sheet 3 Filed March 19, 1957 um. MS WEEN /N ATTORNEY June 27, 1961 R. E. cARREL 2,990,015

sucTIoN Box covERs Filed March 19, 1957 4 Sheets-Sheet 4 FIG.II

INVENTOR.

Ralph E. Carrel United States Patent O 2,990,015 SUCTION BOX COVERS Ralph E. Carrel, 2901 Danville St., Hopewell, Va. Filed Mar. 19, 1957, SerrNo. 647,117 1 Claim. (Cl. 162-367) The invention is of utility inany art in which a filter i screen, driven over a suction box would be useful for thickening'material or extracting liquid. For simplicity of exposition, however a paper-making machine will. be referred to.

In the manufacture of paper and allied products, particularly on the wet end of a machine known as a-Fourdrinier, di'iculty has long been experienced with the rapid wear of the wire-screens due to thefriction between these screen belts and the suction boxesvused to remove the water from the pulp. It is necessary,l particularly on high speed machines, to renew theseA screen belts very often, and as the screen belts are expensive this isan'important item in the cost of manufacturing paper. Furthermore, the extra power requiredV to operate the' Fourdrinier due to ythis friction is considerable.

A Fourdrinier screen is made inthe form of an endless horizontal belt'running over a-driver' drum, usual-ly asuction roll, and idler drums tol support andkeep it tight. 'Ihe top or tight side is further snpportedby free-running table rolls and by several flat boxes, which are boxes rectangular in section in which is maintained a partial vacuum. Paper pulp mixedwith a large percentage of water is fed-@onto the wires at one end. Some of this water drains through the wires as it passes alongV over the table rolls and a large amount is drawn out by suction as the Wires pass over the a'tboxes. This screening-and feln'ng action forms the sheet of paper, whichA is further processed in subsequent operations. The tops of the flat boxes which are in contact with the wires are usually of hard wood, sometimesr impregnated with a lubricant in the presence of Water. The heavy suction pressure, however, between the rapidly moving wires andthe top of the boxesproduces a considerable drag, which results in friction and Wear. istwell known inthe art.

Many attempts have been made to produce' flat boxes equipped with rollers under the wires to-overcome these diculties. These devices have been only partially successful on slow movingipaper machines, and nothing has been produced as yet that is satisfactory for high' speed machines.

One of the principal troubles in' making sucha device lies` in the fact that thev at box rollers supporting the Wire must be close'together, or too great a sag or deection of the wire willl occur between rollers. This requires rollers of small diameter arranged close toA one another. It has heretofore been customary to support such rollers from endv bearings only. As commercial paper machines a very wide, requiring rolls ranging from 8 feet to 20 feet or'more in length, too great a deectionVv results when small diameter rollers are used'. Difficulty has also been experienced in sealing the roller equipped boxes against air leakage.

Therefore, it is of primary concern in connectionwith this inventionV to provide improvements in suction box covers wherein the cover isV so constructed as to minimize frictional drag upon the screen belt andl wherein this is accomplished without sacricing proper and effective support of the screen as it passesover the cover.`

Another object of this invention is to provide improvements in suction box covers wherein the utilization of small diameter rollers is realized without sacrificing rigidity of the same in supporting the screen belt.

Another object of this invention in conformity with the preceding object for the utilization of end as well as intermediate support elements for the small diameter rollers so as to obviate sagging or undue deflection therein.

Still another object of this invention is to provide an improved seal for suction box covers' to avoid undue wear upon the screen and to consequently impartV greater longevity thereto.

Another object of this invention is to provide opposite side edge seals for screen belts which take theI form of endless belts travelling with the screen belt and providing sliding sealed engagement with the suction box cover rather than relyingv upon a` sliding engagement between the screen belt and a stationary seal member which would tend to produce yabnormal wear upon the edges of the screen belt.

As this invention may be embodied in several forms without departing fromr the spirit or essential characteristics thereof, the present embodiment is, therefore, illustrative and not restrictive, since the scope ofthe invention is defined by the appended'claims rather than by thedescription preceding them, and all changes that fall. within the metes and bounds of the claim or that formA their functional aswell yas conjointly cooperative equivalents, are therefore intended to be embraced by this claim.V

In the drawings:

FIG- l is -a plan view of a portion of the improved suction box cover constructed in accordance with this invention;

FIG. 2 is a side elevational view of the improvedfsuction box cover with portions thereof broken away to show details of internal construction;

FIG. 3 is an enlarged sectional view taken substantially along the plane of section4 line 3-3 of FIG; l;

FIG. 4 is an enlarged transverse sectional view taken along the plane of section line 4-4 in FIG. 1 and illustnating the mounting of andl relative relationship of the supporting rollers; i

FIG. 5 is a plan'view of one of the supporting rollers;

FIG. 6 is anenlarged' sectional view taken through one of the roller supporting elements and showingthe details of construction thereof;

FIG. 7 shows one of the roller supporting elements in elevation with portions thereof broken away to further illustrate details of internalY construction; and

FIG. 8 is a perspective view of one end of a roller supporting element.

FIG. 9 is -a partial plan view of' one corner of the assemblage and showing the sealingstructure in this region;

FIG. 10 is a sectional view showing the corner of FIG. 9 partially in elevation;

FIG. 11 is a sectionalzview taken along the plane of section line 11--11v in FIG. 9 and further illustrating details ofthe seal assembly; and

FIG. 12 is a transverse sectional view taken through a modied form of'belt construction.

Referring now more particularly to FIGS. 2 and 4, reference numeral 10 indicates in general the lower portion of a suction box whichV can be constructed in any conventionall manner. That is, the structure designated by the reference character 10 designates the lower portion of a conventional suction box and forms` no part of the present invention. However, the cover for the suction box assembly as is designated generally by the reference character 11 and which forms structurally the upper portion ofthe suction box and upon which the screen belt is supported as the same travels across the suction box assembly. It will be appreciated that the upper edge 12 of the conventional or lower portion of the suction box may take many dilferent forms in accordance with the particular design of the original unit and that therefore, the cover assembly 11 must, of necessity, be accommodated to lit upon such supporting ledge or shelf in accordance with the design of conventional unit. For I the purpose of mounting the cover assembly on the particular type of lower Iportion of the suction box as is shown and illustrated in the drawings, the enclosing side wall 1.3 o f the cover assembly is provided completely around-its 4lower edge with au inwardly' directed ange 14 this" ange resting upon the upper surface of the Vaforementioned shelf 12 and being rigidly aflixed thereto by `means of the fastening elements 15. In FIG. 4, reference character 16 indicates the top edge of the enclosingside wall structure 13, the same, of course, being open both at top and bottom so as to communicate with the suction box chamber 17 which is maintained under partial'vacuum during operation of the machine.

As is shown most clearly in FIGS. 1, 3 and 4, the cover assembly is provided with a plurality of longitudinally extending and laterally spaced support assemblies 18 which extend between the fore and aft portions of the enclosing'wallV structure 13 and are rigidly secured thereto -so to form ian integral-part of the cover as- -sembly. Each of these'supporting assemblies includes a relatively rigid base portion 1'9 which is formed throughout its length and on opposite sides thereof with a plurality of'vertically projecting ears 20 and each laterally spaced pair. ofsuch-.earssupports a truunion member 21 so that thereareprovided a iseries of longitudinally spaced trunnion members oneachsupport assembly with the several trunnions on each support assemblyibeing disposed in transversealignmentsoA as 'to support the intermediate portions Vof av plurality of rollers as indicated most clearly in FIGS. 2 and 4, the latter rollers being indicated by the reference character 22. These rollers 22 are of relatively small diameter so 'that they form rather closely spaced hues of support for the overlying screen belt 23 and, therefore, prevent sagging of the screen between adjacent rollers as the same is supported thereon. At the same time, the rollers are permitted to rotate, as hereinafter describedin accordance with the linear speed of the tion between the rollers 22 and the screen butrather only la rolling relationship so as to 'reduce to a frictional drag of the screen upon the rollers. This permits the machine to be operated at a much greater speed and with less power loss and, furthermore, increases the effective life of Vthe screen 23 since the same is not continually subjectedvtosliding frictional contact with `any portion of the suction box cover which would tend to wear out the Screen, Y .Y Y n u (Each of the support members has its Vbase portion 19 rigidly axed to theopposite waljl portions of the enclosing structl-1re` 13 preferablyby means of the bolts24 and 25 which project longitudinally from opposite endsy of the Abase 19 andvthrou'ghythe associated wall portions 13. 'Ehe undersurface of the base 19 at opposite ends thereof is cut away or notched as Aat 26 and 27 so as to receive the heads 28 and 29V of the bolts and the opposite ends of the base are provided with the notches 30 andV 31. so as to permit the boltswto be initially inserted in place, see particularly FIG. 3. 'Ihe bolts 24 Iand 25 are secured by suitable nuts on the outer side of the wall structure 13 as is shown most clearly in FIG. 4.

- llhenvarious supporting assemblies 18 are spaced laterally thropghoutrthe center or intermediate lportion of the suction vbox cover assembly and at a distance Iapart suflicient to lprovide the necessary support for the individual rollers`22A to'V prevent any undue sagging or deflection thereof caused by the weight of theiscreen 23 and the paper pulp or web on top ofthe screen.

The construction ofreach individual trunnion is illustrated most clearly in FIGS..6 and.7. it willbe seen that .the ears 20 are provided with aligned apertures for receiving the opposite ends of a hollow pin member'32 which is held rigid with the ears by means of In these figures, y

n 4 forms a rigid journal for the remainder of the trunnion assembly which surrounds the same. 'I'he trunnion proper preferably embodies a cylindrical sleeve 35 of Teflon or the like preferably for the purpose of attaining a good bearing relationship upon the metal pin 32 and embracing the sleeve 35 is a resilient cover 36 which may take the form of a resilient rubber sleeve. Preferably, the inner surface of the Teonor similar material sleeve 35 is provided with a plurality of longitudinally extending grooves 37 for the purpose of receiving lubricant during operationof the trunnions. It is important to note that each trunnion projects a slight distance above the associated Aears and for this purpose the uppermost edge of each ear is preferably formed of a uniform radius which is of slightly less than the outer surface of the cover member 36. This is shown most clearly in FIG. 4.

Each of the rollers 22 is constructed in-accordance with the showing of FIG. 5 wherein it will be seen that each includes an enlarged intermediate body portion 38'Which is hollow and provided with a plurality of openings 39 in the surface thereof for the purpose which will 4bevpresently apparent. Preferably, the opposite ends of each body 38 receive journalling rods 40 and 41 each of f which terminates in a portion V of uniform diameter for reception within bearing blocks such as those illustrated generally by the reference character 42 in FIG. 3. On one of such journal members 41, there is preferably provided Yat the opposite' ends of the bearing surface 43 i 4 thereof a pair of radially projecting shoulders orcollars 44 and 45 `which serve to locate each roller axially and, of course, the corresponding journal blocks 42 must be ofthe split type to accommodate this end of the roller with the particular construction shown since the shoulders 44 and 45 are integral with the journalling portion 41.

The opposite end of each roller is similarly journalled but is free to shift axially to accommodate for longitudinal expansion and contraction ofthe rollers without buckling.

That portion of each journal end' assembly 40 or.41

screen 23'solthat -atno time is there any real linear mo- 3 disposed most closelyv adjacent the associated end. of

the' roller'body' 38 is provided with an enlarged shoulder portion- 46v or 47'each of which'has a frusto-conical outerface, as indicated by the reference characters 48 and 49. The purpose of these frusto-conical faces is to engage against the beveled side edge of sealing belt members disposed along opposite sides of the machine, one of such belts being indicated by the reference character 50 in FIGS. 1-4. In FIG. 3, each belt 50 will be seen to be provided with the opposite side beveled edges 51 and 52, the former of whichrengages against the aforementioned frusto-conical surface v49 on thejournal end portion 41 of the associated roller assemblies 22 and the latter side` of which engages against the outer inclined face 53` of a downwardlyprojecting lip 54 of the side piece'indicated generally by thereference character 55.

a pair of set screws 33 and 34 which bear against the i Tw'o Asuch'side piecesare provided-for the cover and extend along the opposite longitudinal edges of the same. In the particular example shown, each such side piece includes a vertical wall portion 56, :an inwardly directed horizontalwall portion 57 and the aforementioned lip 54 which ,isintegral' with the inner edge ofthe wall portion 57,.;` 'Fori-the'purposeL-of mounting these side pieces and for providing a support for the aforementioned bearing blocks 42, the side walls 13 of the cover are provided, along the opposite longitudinal sides of the cover with outwardly extending horizontal ledge portions 58 which are disposed in spaced parallelism above the underlying ledges 59 and overhang the same. The ledge portions 59v correspondto the' previously mentioned anges 14 which rest upon the uppersurface of the' lower portion of the suction box, the' ledges or anges 59 serving the same purpose. The side pieces 55 are secured as by fasteners 60 tothe outer edge of the ledges 58 as is shown most clearly in FIG. 3 :and the space between the ledge 58 and the underlying ange 59 serve to accommodate for the lower flight of the belt 50, the same being of endless form and beingA trained about the pulleys A61 and 62 at opposite ends of the-suctionl boxas isv shown most clearly in FIG. 2. l

Each pulley 61 and 62 is driven by a suitable means, being fixed to the shafts 63 and 64 respectively which are supported by means of the brackets 65 and 66, suitably mounted as -by fasteners 67 and 68 through their base portions 69 and 70. Also xed to the shafts 63 and 64 are a pair of sprockets 71 and' 72 and trained about these sprockets and extending over corresponding sprockets 73 and 74 are endless chain members 75 and 76. The two end rollers 77 and 78, see FIG. 4, are imperforate throughout their main body portions and each has one journal end thereof elongated to project outwardly through one of the side pieces S5 and upon which the sprockets 73 and 74 are xed. These two end rollers are therefore positively driven by means of the same shafts which drive the belt and all of the intermediate rollers are driven positively also by virtue of their engagement with the upper flight of the belt 50 and through intermediate supporting rollers 21, all rollers being driven in the same direction.

It is to be noted that the screen belt 23 is of a width greater than the lengths of the main body portions 38 of the rollers 22 and that the opposite side edges extending laterally to overlap a substantial amount of the upper iiight of the belt 50, see particularly FIG. 3.

To provide seals at the opposite ends of the suction box, across the wall portion 13 at each end of the cover is mounted an angulated support plate 79 and affixed to each support plate is a flexible sealing strip 80 which projects beyond the free edge of the plate 79 and engages along the outer surface of an associated end roller 77 or 78. It will be noted that the upper flights of the belts 50 pass over the lines of contact between the sealing strips 80 and the end rollers 77 and 78 so as to permit sealed engagement throughout the entire lengths of the end rollers such that the belts together with the sealing strips 80, positively seal the assemblage around the entire periphery thereof.

As is shown most clearly in FIGS. 9, and l1, a specially constructed sealing means is utilized to seal the corner regions of the cover assembly where the belt 50 passes outwardly fore and aft from the cover. In this construction, each corner of the cover is provided with a wall member indicated generally by the reference character 81 which extends inwardly from the previously mentioned vertical wall portion 56 as is shown mos-t clearly in FIG. lO and is so constructed as to fit snugly against the inner surface of the wall portion 56 and being secured to this assembly by means of suitable fasteners such as those indicated by the reference character 82. The upper edge of this wall assembly 81 is notched in the manner shown most clearly in FIG. 10 with the opposite side walls dening such notch being angulated in accordance with the opposite beveled sides of the belt 50 and similarly to the angularity of the inner wall portions 53 and the angularity of the beveled surfaces 49 on the rollers. Preferably, the belt engaging surface of this notch is covered with strips 83 of bearing material such as Teon or the like so as to minimize wearing of the undersur-face and opposite sides of the belt.

integrally formed with each of the wall assemblies 81 and at the inner side thereof is a laterally outwardly extending portion `84 which preferably terminates at the corresponding end edge of the cover assembly as is shown most clearly in FIG. 9. The inner face 85 of the wall extension 84 provides a seal in conjunction with the corresponding end edge of the supporting strip 79 and sealing strip 80 to seal along the associated side edges of these members so that the corners of the cover assembly are substantially completely sealed with the exception of very small areas located adjacent the corner edge portion 86 of the wall assemblies 81.

Consequently, the assembly achieves-'a very effective seal throughout the entire region thereof withoutV resorting at any time to any large areas of slidingv frictional contacting surfaces which will unduly wear' the component parts. As a matter of fact, the only parts which are subjectedto sliding frictional contact at any point in" the assembly are the belts 50 and then provision -has been made to minimize the effect of this frictional contact by the provision of suitable bearing surfaces adjacent which the belt is contacted.

The modification shown in FIG. 12 illustrates one manner in which fthe belt can be constructed so as to provide a more eiective outer side seal. In this figure, the belt is indicated by the reference character 90 and, as will be seen, its inner edge 91 is constructed in accordance with the showing of FIG. 10, whereas on its outer side 92, the belt is provided with a longitudinally extending upraised portion 93 which effectively widens the outer sealing edge face portion 92 so as to establish a greater width of ysealing engagement Iwith the rollers and elements with which this side of the belt comes in contact.

I claim:

In a suction box for sealingly supporting a traveling conveyor screen against suction, in combination, a top structure having a forward transverse wall, a rearward transverse wall, and a pair of longitudinal side Walls; a plurality of transversely extending screen supporting roller members including a forward terminal roller member and a rearward terminal roller member, each roller member having an intermediate screen supporting portion and reduced end portions defined by a bevelled shoulder; means for turna-bly supporting said roller members upon said side walls of the top structure comprising a shelf portion extending outwardly from the ytop end of each side wall of the top structure substantially along the length thereof, and journal means mounted on each shelf structure for turnably supporting the outer ends of the reduced end portions of said roller members; a forward and a rearward pulley carried by said top structure at each end of each side wall of the top structure; a pair of endless sealing belts each having a pair of longitudinal edges formed at opposite sides thereof, said longitudinal edges of each belt being bevelled opposite one another, each belt having carried along a respective side wall by a respective forward and a respective rearward pulley with the upper strand of each belt supported by respective reduced end portions of the roller members so that the top face of the belt is disposed substantially ush with .the adjacent outer peripheral portions of the associated roller members such that the upper strand of each belt is adapted to sealingly support the respective edge portion of fthe associated screen with the screen being maintained in a flat condition throughout by the rollers and top sides of the upper strands of the belts, the return strand of each belt passing underneath the associated shelf, means for sealing the upper strand of each sealing belt yagainst suction along the associated side of the top structure comprising a casing structure together with said shelf portion enclosing the adjacent journal means and having a longitudinal inwardly facing wall pontion at each end thereof, and comprising a top wall portion overhanging said journal means and for-med with a bevelled edge portion opposite to said bevelled shoulders so that the bevelled edges of said sealing belt engage said shoulders and said stationary bevelled edge portions; and transverse sealing means carried by each transverse wall of the top structure and extending substantially along the length thereof into sealing relationship with the respective forward and rearward terminal rollers, with each transverse means endwise confined between a pair of said inwardly facing wall portions opposite to one another in sealing relationship therewith, so arranged that said inwardly facing end wall portions together with said sealing belt and said terminal roller "7 members in Contact with said screen dene a suction area relative thereto.- 1 Y Y I References Cited in the file of this patent UNITED STATES PATENTS 256,047 Randall Apr. 4, 1882 316,221 Barber Apr. 21, 1885 ,528,261 Sanderson Oct. 30, 1894 Shearer Mar. 6, 1900 Witham -..f v ;.'lFeb. 15, 1916 Severini Feb. 3,k 1931 Staudenmaier Apr. 8, 1958 FOREIGN PATENTS Great Britain ..-,Nov. 12, 1890 Norway July 7, 1930 

